Abstract.The major challenge when integrating information systems in any domain such as e-Government is the challenge of Interoperability. One can distinguish between three aspects of Interoperability; technical, semantic, and organizational. The technical aspect has been widely tackled especially after the ubiquity of internet technologies. The semantic and organizational aspects deal with sharing the same understanding (semantics) of exchanged information among all applications and services, in addition to modeling and re-engineering governmental processes to facilitate process cooperation that provision seamless e-government services. In this paper, we present the case of the Palestinian Interoperability Framework ‘Zinnar’, which is a use case of using ontology in e-government (i.e., data and process governance) to tackle the issues of semantic and organizational interoperability. The followed methodology resulted in a success story within a very short time and has produced a framework that is intuitive, elegant, and easy to understand and implement.